Known methods of multiplexing a sound sequence signal with an analog video picture signal make use of techniques for digitizing audio samples and for time-division multiplexing signals in logic states which correspond to digital quantization of each audio sample with the analog video picture signal over the active lines of the video signal (code and pulse modulation).
However, these known encoding techniques limit the transport capacities of the analog video picture signal by the duration of the sound sequences inserted in each active line of the picture signal, with these limitations being due essentially to the method of encoding the audio samples.
Consequently, the object of the invention is to mitigate this drawback and in particular to significantly increase the duration of sound sequences inserted in each active line of the analog video picture signal by optimizing utilization of the amplitude dynamic range of the video picture signal for encoding the audio samples, with said duration being about 8 seconds of telephone quality sound per picture field on a channel for transmitting an analog video picture signal having a base bandwidth of 5 MHz and a dynamic range of less than 50 dB.